Baars P A, Maurice M M, Rep M, Hooibrink B, van Lier R A
Department of Clinical Viro-Immunology, Central Laboratory of the Netherlands Red Cross Blood Transfusion Service, Amsterdam.
J Immunol. 1995 Jan 1;154(1):17-25.
CD27, a member of the TNFR family, is expressed on most but not all peripheral blood CD4+ T cells. The small fraction of CD4+ T cells with a CD27- phenotype exclusively reside within the CD45RA-CD45RO+ subset. We previously provided evidence that CD27- cells are functionally differentiated cells that have lost CD27 expression as a result of persistent antigenic stimulation. We here show that compared with CD4+CD45RA-CD27+ cells, CD4+CD45RA-CD27- lymphocytes have a high expression of the beta 1 integrins VLA-4 and -5 and of the beta 2 integrin CD11b. Molecules implicated in homing of T cells to peripheral lymphnodes like CD31 and CD62L (L-selectin) are poorly expressed on CD27- cells, whereas receptors involved in organ-specific homing, e.g., cutaneous lymphocyte Ag and HML-1 (alpha E beta 7), are present on CD27- rather than CD27+ T lymphocytes. CD27+ and CD27- cells do not differ notably in the expression of activation molecules such as CD25, CD38, and CD70 (CD27 ligand) but CD7 is markedly absent on approximately half of the CD27- cells. Analysis of mutations in the HPRT gene, as measurement for the amount of cell divisions that have occurred in particular T cell populations in vivo, showed that CD45R0+ cells have a 2 to 5 times higher mutant frequency than CD45RA+ cells, whereas CD45R0+CD27- cells do not differ in this respect from CD45R0+CD27+ cells. In line with this latter finding, cells in G2M phase can only be found in the transitional, CD45RAbrightCD45R0bright subset but not in CD45R0+, CD45RA-, or CD27- cells. Our results imply that the CD27- population contains tissue-specific, specialized "primed" T cells that evolve in vivo independently from extensive cellular division.
CD27是肿瘤坏死因子受体（TNFR）家族的一员，在大多数而非全部外周血CD4+ T细胞上表达。一小部分具有CD27阴性表型的CD4+ T细胞仅存在于CD45RA-CD45RO+亚群中。我们之前提供的证据表明，CD27阴性细胞是功能分化的细胞，由于持续的抗原刺激而失去了CD27表达。我们在此表明，与CD4+CD45RA-CD27+细胞相比，CD4+CD45RA-CD27-淋巴细胞高表达β1整合素VLA-4和-5以及β2整合素CD11b。参与T细胞归巢至外周淋巴结的分子，如CD31和CD62L（L-选择素），在CD27阴性细胞上表达较低，而参与器官特异性归巢的受体，如皮肤淋巴细胞抗原和HML-1（αEβ7），则存在于CD27阴性而非CD27阳性T淋巴细胞上。CD27阳性和CD27阴性细胞在激活分子如CD25、CD38和CD70（CD27配体）的表达上没有显著差异，但约一半的CD27阴性细胞明显缺乏CD7。对次黄嘌呤-鸟嘌呤磷酸核糖转移酶（HPRT）基因突变的分析，作为体内特定T细胞群体发生细胞分裂数量的衡量指标，显示CD45R0+细胞的突变频率比CD45RA+细胞高2至5倍，而CD45R0+CD27阴性细胞在这方面与CD45R0+CD27阳性细胞没有差异。与后一发现一致，处于G2M期的细胞仅存在于过渡性的CD45RAbrightCD45R0bright亚群中，而不存在于CD45R0+、CD45RA-或CD27阴性细胞中。我们的结果表明，CD27阴性群体包含组织特异性的、专门的“致敏”T细胞，它们在体内独立于广泛的细胞分裂而进化。
